Facing economic uncertainty, the tribe took the government to court and won a preliminary injunction that allowed the casino to open for the busy Labor Day weekend in 2007. A year later, a federal judge rewarded the tribe with a final decision that upholds the legality of the site.

In the 37-page ruling, Judge R. Allan Edgar said the government "dropped the ball" by failing to resolve a bureaucratic blunder dating to 1986 that would have prevented the litigation altogether. He said the casino site qualifies for gaming because it is "contiguous" to an existing reservation, as allowed by IGRA.

"Defendants appear to ignore any case law that discusses the meaning of reservation in any context and instead rely on their own inability to make a decision on a timely request for a proclamation as evidence of the lack of merit of the request," Edgar wrote.

IGRA generally bars gaming on land taken into trust after 1988 unless certain exceptions are met. The Kewadin Shores site was acquired in 2000, well past the IGRA deadline.

The tribe argued that the site qualifies because it is contiguous to land that was placed in trust 1983, long before the passage of IGRA. The tribe even asked the Bureau of Indian Affairs for a proclamation to declare the 1983 parcel a reservation in 1986, two years before IGRA became law.

Despite the history, the NIGC issued a series of opinions that said the 1983 site was not a reservation. Attorneys from the Interior Department weighed in and said the only way for the 1983 site to be considered a reservation was for the BIA to formally declare it to be one.

The government's stance meant the 2000 parcel could not be used for gaming without going through an additional, lengthy review process that only three tribes have completed in the history of IGRA.

But Edgar said the BIA's inaction shouldn't be held against the tribe. He said ambiguities in the definition of "reservation" tipped the case in the tribe's favor.

Edgar noted that the BIA's recent IGRA regulations appear to bring some certainty to the issue. The Section 20 rules, however, were finalized long after the tribe applied for its reservation proclamation, he said.

As a result, "this court must review the defendants' actions at the time of the decision, not in hindsight," Edgar wrote.

A similar case involving the Fort Sill Apache Tribe of Oklahoma is pending in federal court. The tribe asked the BIA for a reservation proclamation for land held in trust in New Mexico.

The BIA failed to act on the proclamation even as the tribe moved forward with plans for a gaming facility. A judge has so far declined to force the BIA to make a decision.